Geographic distribution of male colorectal cancer. The fill color in each ZIP code represents the SMR, with green indicating relatively low SMR and purple representing relatively high SMR. White ZIP codes indicate SMR near 1 (observed and expected equivalent). The ZIP codes outlined and cross-hatched in orange had significantly high incidences and formed local clusters under Moran's test. The ZIP code outlined and cross-hatched in yellow is a significant spatial outlier in the local Moran analysis, though its confidence interval is not significantly different from 1. The black outlines describe ZIP code boundaries. Labels identify the centering ZIP codes for each cluster or outlier.